(i) Field of the Invention
The present invention relates to an instrument to enable a metal worker to perform flat layout patterns by marking the relevant lines directly on sheet metal stock, i.e. to mark the total length of the sheet metal stock and to mark the sight line for bending the sheet metal stock, very accurately and quickly. The invention is especially useful for, but is not limited to, 90.degree. bends.
(ii) Description of the Prior Art
Analogous art includes many patents for scales or charts to provide a short cut for calculation. For example, Canadian Patent 75,600 patented Apr. 12, 1902 by J. M. Daly provided a scale-chart for graphically computing the tonnage resistance of trains of cars, including a chart arranged with devices or signs in successive order for indicating tonnage and a supplemental scale for indicating tonnage hauled.
Canadian Patent 133,733 patented June 13, 1911 by D. H. Layne provided a computing yard-measure provided with graduations, along one of its longitudinal edges, and transverse columns of figures arranged in pairs.
Canadian Patent 165,067 patented Sept. 21, 1915 by W. Zurich provided a framing tool comprising a rectangular plate having its face laid off to form reversely disposed squares, a table or scale columns disposed between the squares and having scale indicia, and markings within the area of the squares indicative of pitches.
Canadian Patent 212,135 patented May 31, 1921 by L. Smith provided a packet formed with a base plate fashioned with upturned ends and inwardly extending retaining flanges, a series of data cards pivoted on a common centre in one flange with their opposite ends under the inwardly extending flanges, and an upturned end on the flange at the opposite end of the base plate to guide the free ends of the cards.
Canadian Patent 383,933 patented Sept. 12, 1939 by J. Palmer provided bulk band gauges for a horizontal layout, including an elongated gauge body, graduators extending transversely of the gauge body, and scale indicia associated with the graduations and occupying at least two parallel zones extending longitudinally of the gauge for reading successively therealong.
U.S. Pat. No. 2,656,099 patented Oct. 20, 1953 by H. J. Selling provided charts for determining the proportions of three additively primary reacting colour dye stuffs required to produce a given colour. The charts each showed a series of constant concentration curves for one dye with respect to the concentrations of the other two dyes, for different preselected X,Y and Z stimuli of the eye.
U.S. Pat. No. 3,134,540 patented May 26, 1964 by E. M. Shiepe provided a nomographic computory device including a first panel having associated with the surface thereof a plurality of mathematically correlated reference line coordinates each related to a variable and each having indicia associated therewith setting off a fixed scale. A second panel was provided upon which the first panel was superimposed, the second panel having a plurality of groups of moduli scale quantities with the scale quantities in each group arranged in vertical and horizontal rows and mathematically related to a particular line coordinate on the first panel. A plurality of windows were provided on the first panel, each for revealing a scale quantity and each correlated in position to a particular line coordinate and its corresponding group of moduli scale quantities on the second panel.
U.S. Pat. No. 3,269,649 patented Aug. 30, 1966 by L. Abel provided numerographical apparatus for the systematic determination of the relationship between a plurality of co-related variables comprising a fixed table having a plurality of fixed parallel graduated logarithmic scales of the same modulus, a light permeable screen disposed over the table and a plurality of reading windows on the screen.
U.S. Pat. No. 3,559,881 patented Feb. 2, 1971 by R. L. Maison provided a nomographic instrument for solving mathematical problems. It included nomograms that enabled the manipulation of a straight line to read off the value of a dependent variable when the value of an independent variable was given, thereby computing, by means of graphic representation, systematic solutions to the problems capable of numerical calculation. The scales were immovable and the calculating line was moved by manipulations to intersect the scales at read-off points where memory indicators are positioned for reference. A plurality of calculating lines and a multiplicity of memory indicators operable at each and/or both sides of the instrument.
U.S. Pat. No. 4,122,994 patented Oct. 31, 1978 by M. B. McReynolds et al provided a computerized aid for determining the optimum cycle lengths for use in a vehicular traffic control system wherein inbound and outbound traffic flow are equally favored. The aid was a nomograph which provided a clear visual indication of candidate optimum cycle lengths for a particular group of intersections which required only prior knowledge of intersection relative locations. The graphical computational aid provided, in addition to the candidate optimum cycle length information, a visual indication of the quality of the candidate solution obtained for each of the controlled intersections of the group.
U.S. Pat. No. 4,203,542 patented May 20, 1980 by C. F. Corbett provided a calculating apparatus including a first body member having a first linear scale. The first body member had both a horizontally-elongated opening and a vertically-elongated opening. A second slidably member was provided having a second scale thereon and a third logarithmic scale. All the scales interacted to simplify the calculation of the required feeder head parameters, e.g. size, amount of antipiping compound, in casting metals. Only the size of the casting section being fed and the normalized inscribed circle relating thereto needle to be measured.